This is stevia extract (white, not the green kind) and is similar in flavor to an artificial sweetener. The thing that gives it a "twist" is, well, obviously the vanilla flavoring.
The vanilla works very will with stevia as it gives it a light vanilla flavor that is barely pronounced, but does make an impact on the flavor. If you're a vanilla junky and want to skip the creamer when you're putting sweetener in your coffee/tea, this will do the trick!